Expression-control device



March 11, 1930. FQRSBERG 1,750,261

EXPRESS ION CONTROL DEVICE Filed April I, 1927 6 Sheets-Sheet l March 11, 1930. FORSBERG 1,750,261

EXPRES S ION CONTROL DEVICE Filed April 1, 1927 6 Sheets-Sheet 2 Gas 2 a?! 2 015 Zer g 6 Sheets-Sheet G. A. FORSBERG EXPRESSION CONTROL DEVICE Filed April 1', 1927 March 11, 1930.

March 11, 1930. G. A. FORSBERG EXPRESSION CONTROL DEVICE Filed April 1, 1927 6 Sheets-Sheet 4 a 6 (YT) IIMU-U March 11, 1930. Q FQRSBERG 1,750,261

EXPRESSION CONTROL DEVICE Filed April 1, 1927 6 Sheets-Sheet 5 March 11, 1930. FORSBER G 1,750,261

EXPRESSION CONTROL DEVICE Filed April 1, 1927 6 Sheets-Sheet 6 'gfe -M4M,P y

Patented Mar. 11, 1930 UNITED STATES PATENT OFFICE GUSTAV A. 'FORSBERG, OF CHICAGO, ILLINOIS, ASSIGNOR T0 GULBRANSEN COMPANY,

0F CHIC-AGO, ILLINOIS, A CORPORATION 10]! ILLINOIS EXIEIRESSION-CONTROL DEVICE Application filed April 1, 1927.. .Serial No. 180,103.

This invention relates to player pianos, more particularly to a device for automaticaL 1y controlling the expression of such instruments.

There are many expression control devices for use in connection with player pianos, but such devices are not .altogether satisfactory in that they are slow in action and do not respond readily and promptly 'in'such manner as to vary the tone quality at precisely the proper time. This objection is avoided in my control device by providing a. suction chamber which is normally closed to the atmosphere, atmospheric .air being admitted into the suction system only at such times as the tension in the system reaches a predetermined value, the admission of atmospheric air being controlled by means responsive to the tension in the system, such means being controlled to automatically admit atmospheric air at any one of a plurality of selected values of tension in the system. In effecting this result, I provide a plurality of expansible members disposed within a suction chamber to be subject .to the tension therein, these members being independently operable to open individual air inlet valves and responding to difierent tension values in the "suction chamber. In conjunction with these expansible members I provide valve means for controlling the same through the medium of openings in the tracker bar ofthe piano and a perforated music sheet passing over this bar. The device as a whole is of. simple and inexpensive construction and the parts are so arranged that the various air passages are short and straight to reduce resistance to flow of the air insuring quick and accurate operati on. Further objects and advantages will appear from the detail description.

In the drawings 2- Figure 1 is a front view of a player piano of known construction with the front boards removed showing the control device applied;

Fig. 2'is a semi-diagrammatic view showing the connections between the control device, the tracker bar, the stack, and associated parts;

3 is an underneath view of the control device partly broken away;

Fig. l is a section taken substantially on line 4-l of Fig. 9, parts being shown in elevation;

Fig. 5 is a plan view with parts removed, this view being taken substantially on line '55 of Fig. 9; V

Fig. 6 is a plan view of the suction chamber cover showing the pneumatics carried thereby and associated parts, taken substantially on line .6-6 of Fig. 9, the valve operating fingers being shown in plan;

Fig. 7 is a plan view of the suction chamber showing the air inlet control valves, this view being taken substantially on line 77 of Fig. '9;

Fig. 8 is a section taken substantially on line "8--8 of Fig. 3;

Fig. 9 is a section taken substantially on line 9-9 of Fig. 3;

Fig. 10 is a plan view of the valve block, partly broken away;

Fig. 11 is a section taken substantially on line 11-11 of Fig. 3;

Fig. 12 is a section taken substantially on line 12-42 of Fig. 3;

Fig 13 is a section through the relief valve structure; and

Fig. 14 is a section taken substantially on line 1l114 of Fig. 13.

For the sake of illustration, I have shown my expression control as used in connection with a player piano of known construction, but it will be understood that this device can be used in connection with pneumatically actuated instruments other than player pianos. The piano illustrated is of the reproducer type and includes an exhausting power unit including exhaust bellows Z) of known type, an electric motor for operating the exhaust bellows, the throat, a gate valve for the throat, and associated parts, all of known construction and operation. A conduit 1 extends from one end of the throat of the exhaustand power unit or bellows system and establishes communication between throat 2 and channel board 8 of the pneumatic stack at one end thereof. A pulley 4 is keyed on shaft 5 of motor '6 and is connected by a cord 7 to grooved pulley 8 keyed on crank shaft 9 of the exhaust unit, the bellows I) being connected to the crank shaft in proper order to maintain a constant tension in the suction system including the roll motor and the channel board. This board has associated therewith the player pneumatics which are arranged in tiers 1n staggered relation and are controlled from the tracker bar through suitable valve means for actuating lifting levers through suitable onnecting links, the lifting levers operating the hammer mechanism; all in a manner well known in this art. The force with which the player pneumatics act, and consequently the loudness of the music produced, will depend upon the amount of vacuum or tension in the channel board. To prevent this tension from exceeding a predetermined maximum a relief valve is provided. This valve is adjusted to open and admit air'into the channel board suction system when the tension in the channel board reaches the predetermined maximum, at which time the note struck will be of maximum intensity or loudness. It is the common practice, in player pianos, to vary the intensity or loudness of the note struck by varying the tension in the vacuum or suction system of the stack. This result is accomplished by admitting more or less air into the system,'causing a corresponding variation in the tension thereof and consequently a corresponding variation in the force with which the hammers are operated. My invention relates more particularly to the method and means for admitting air into the stack system in such manner as to obtain instantaneous changes in the degree 'or value of the tension therein giving instantaneous and accurate regulation of the volume or intensity of the note produced.

In Fig. 1 of the drawings I have shown my control device, indicated generally by 10, as situated beneath and adjacent the left hand end of the key bed, though it will be understood that it can be positioned in any other suitable location. This device is of box-like construction and includes an upper mufller section 11, a lower suction chamber 12, a cover 13, and a valve block 14 secured on the cover. This valve block is secured to the cover by screws 15 and the muffler section and the suction chamber and the cover, therefore, are secured together in a similar manner, screws 16 passing through the'ends of the mufiler and securing it to the suction chamber, and screws 17 passing through the cover 13 and securing it to the top or upper side of the suction chamber. To insure an air tight closure between these various sections and associated parts, suitable packing members or gaskets of felt, leather, or other suitable material, are disposed between such members. The mufiler is provided, approximately midway between the top and bottom thereof, with a bafile 18 extending throughout the whole cross area of the muffler and provided at one end with a plurality of openings 19 for admitting air above the battle, the top wall 20 being provided adjacent the other end thereof with a plurality of similar openings 21. To avoid vibration and undesirable noises suitable nipples 22 of felt or other suitable cushioning material are secured through the openings 19 and 21. When an air inlet control valve of the suction chamber opens, air is drawn through the mufiler into the chamber from which it is admitted into the suction system.

The suction chamber 12, like mufiler 11, is of box-like construction and is provided with a plurality of air inlet openings 23 extending through its top wall 24 adjacent one side thereof. As will be noted more clearly from Fig. 5, these openings decrease uniformly in diameter from one end of the suction chamber to the other end thereof. There are four of these openings and they are normally closed by flap valves 25 hingedly secured by strips of leather 26 to blocks 27 secured by screws 28 to the upper face of wall 24. The leather strips 26 are of such length as to extend beyond the openings 23 and form facings for the valves which insure an air tight closure about the respective openings when the valves are closed. These valves are urged in closing direction by wire springs 29 secured in the blocks 27 and having their free arms bearing'against the upper faces of the valves and operating in shallow grooves provided therein for this purpose. A leather disc 30 is secured to the under face of each valve adjacent the free end thereof, this disc forming an air tight closure about a small opening 31 through wall 24, these openings being disposed between the other side of the suction chamber and the air inlet openings 23.

Four pneumatics 32 of bellows construction are secured to the upper face of cover 13 and are disposed within the suction chamber so as to be subject to the partial vacuum or tension therein. Each of these pneumatics or bellows has a plate or leaf 33 secured to the expansible element of the bellows for movement therewith, this leaf being secured to the bellows element by gluing or in any other suitable manner. A screw in 34 is secured in leaf 33 centrall thereof and projects upwardly therefrom, this pin assing loosely through the inner end of a leaf spring 35 which bears upon a disc 36 of felt or other suitable cush-- ioning material secured'to leaf or plate 33 about pin 34, this disc serving to eliminate vibration or=undesirable noises. Spring 35 is mounted on a suitable supportingmcmber, such as a screw 37 secured in and projecting u wardl from the cover 13. To provide amp e bearing for the spring the head of the screw may be enlarged or a washer 38, or other suitable element, may be disposed about the screw between the head thereof and the spring. Each spring projects inwardly of 'the suction chamber beyond its supporting screw and is provided at its outer end with an opening of a size to receive the upper threaded portion 39 of an adjusting rod 40, the lower threaded portion 41 of which screws through. the cover 13. A nut 42 is threaded on the upper portion 39 of rod 4.0, threading of this nut onto the portion 39 being positively limited by the unthreaded por tion 43 of rod 40. A washer 44 is mounted about the rod and confined between spring 35 and nut 42. This provides an abutment for the outer end of the spring, the tension of which may be adjusted by screwing the rod through the cover in proper direction, rocking the spring about the fulcrum provided by the washer 38. For convenience in manipulating the rod 40, a knurled thumb nut 45 is secured on the lower end of rod 40 below the cover 13. A cylindrical valve operating finger 46 is secured on each pin 34, this iinger being formed of wood and operating through a felt bushing 47 secured in the opening 31. The finger is disposed to contact with disc 30 and open the valve against the tension of ,wire spring 29 when the corresponding pneumatic or bellows 32 expands. The springs increase uniformly in strength, the weakest spring being associated with the bellows which operates the valve for the largest one of the air inlet openings. As will be noted more clearly from Fig. 6, the pneumatics or bellows 32 decrease uniformly in size fror the largest one of the air inlet openings. When two or more of the bellows are open to the atmosphere, that bellows having the weakest spring 35 will respond to a given tension in the suction chamber, opening the corresponding air inlet valve. By providing suitable means for controlling the admission of atmospheric air to the bellows, the admission of atmospheric air to the suction chamber, and consequently to the suction system, can be varied for controlling the operation of the player pneumatics as previously explained.

The construction of the valve block and associated parts is shown in Figs. 8 to 12. This block is provided in its upper face with three pairs of parallel channels 48 (Fig. 10). In its under face the block is provided with two series or sets of four recesses forming diaphragm chambers 49 and 50 for pilot primary valves and secondary control valves, respectively. Each of the chambers 49 is pro vided with an annular shoulder for recept on of the marginal portion of a valve operat ing diaphragm, this shoulder being shown at 51. Each of the diaphragm chambers 50 is provided with a similar shoulder 52. A vertical passage 53 extends from the top ct each primary valve chamber 49 to the top of block 14, this passage being disposed concentric with the chamber. The bores or passages are disposed midway between the respective pair of channels 48'. and adjacent one end thereof, the first three bores or passages 53 tion channel 62 is of proper from the right hand end of the valve block, as considered in Fig. 10, have direct communication with the corresponding ends of the channels 48 of the respective sets'or pairs of channels by means of short straight open. ings 54. The same ends of the inner ones of the channels have direct communication with the diaphragm chambers 50 of the secondary control valves, beneath the shoulders 52 thereof, by means of relatively short and straight inclined ducts 55. The other bore or passage 53 has direct communication with the lower portion of the corresponding valve chamber 50 through a duct 56. Brass rings or ferrules 57 are secured in the ends of the passages or bores 53 and form seats for the discs of dou ble acting pilot or primary control valves. The channels 48 of each set or pair have direct communication at their other or right hand ends, as considered in Fig. 10, with the diaphragm chambers 49 to the right of the respective pairs of channels, by means of the short ducts 58, these ducts opening into the diaphragm chambers above the shoulders 51 thereof. The block is bored or channeled out at the side thereof remote from the channels 48 to form a suction channel 59, the outer side of which is closed by a relatively thick strip 60 glued or otherwise suitably secured to the side of the block to form an air tight closure therewith. The ends of the channel thus formed are closed by suitable closure plugs 61 glued therein. After the strip 60 has been properly secured in position, a supplemental channel 62 is bored across the block adjacent the left hand end thereof as considered in Fig. 3, this supplemental channel intersecting the channel 59 and also intersecting and opening into the diaphragm chambers 49 and 50 at the left hand end of the block. This construction will be understood from Figs. 3 and 11. The upper portions of the other diaphragm chambers 50 have direct communication with the channel 59 by means of short ducts 63 and similar ducts are provided for the first or left hand diaphragm chamber, though this is not essential if the opening 64 from this chamber into the supplemental sucarea to insure free fiow of air therethrough and the pro duction of proper suction or tension in the various channels sui'iiciently rapid to insure instantaneous operation of the air inlet valve control bellows. The opening 65 between the supplemental channel and the upper portion or compartment of the left hand diaphragm chamber 49 is also of such size as to insure free flow of air therethrough and proper tension for operating the pilot or primary control valve. As will be noted more clearly from Figure 3, each of the chambers 49 is provided with an offset portion forming a pocket 66 in direct communication with the lower portion or compartment of the chamher. The short ducts 67 extend from the GAS ocket to the corresponding channel 48 ad- ]acent the right hand end thereof, a bleed thimble 68 being secured in this duct and opening into the pocket, this thimble being provided with a restricted bleed opening. The thimble 68 opening into the pocket of the last or left hand diaphragm chamber has direct communication with the supplemental channel 62.

The diaphragm chambers 49 and 50, as well as the pockets 66, are closed by strips 69 of rubberized fabric, or other suitable material, glued tightly to the under face of the block to form a fluid tight closure. The channels 48 are similarly closed by strips 70 secured to the top face of the block, and a closure strip 71 is secured to the edge of the block from which the openings 54 are bored, this strip serving to close the dead ends or inactive portions of the openings or, more correctly, of the bores by which the openings are formed. Each of the chambers 49 receives a diaphragm 72 of a pilot or primary control valve 73. This valve is of known type and includes a cruci-form stem 74 at each end of which is secured a leather faced valve disc 75. These discs are disposed for cooperation with the ferrules or valve seats 57. The lower disc 75 is connected to the diaphragm 7 2 centrally thereof by means of a small disc or pellet 76 of leather, or other suitable material, which is glued to the disc 75 and to the diaphragm, the marginal portion of the diaphragm being glued to the under face of shoulder 51 of diaphragm chamber 49. The tubular elbow 77 formed of brass tubing is secured in the block and opens directly into each of the pockets 66 adjacent the bleed thimble 68. These elbows are connected by rubber tubes 78 to four openings 79, 80, 81 and 82 in the tracker bar 83. The music sheet 84 travels over the tracker bar and is provided with suitably disposed perfora tions for admitting air through the tracker bar openings at predetermined times to operate the primary control valves to produce the expression desired. The manner of operating the music sheet and the function of the perforations therein are well known in this art and need not be set forth in detail.

The valve block 14 is further provided, in its upper face, with four recesses forming valve chambers 85 which are disposed concentric with the diaphragm chambers 50. The chambers 85 and 50 are separated by the relatively thin portion or web element 86 of the block, this element being provided with an opening 87 through which operates the cruci-form stem 88 of a valve 89 having a leather faced disc 90 secured to the upper end of the stem and operating in the valve chamber 85. This disc operates between web 86 and a valve ring 91 secured by gluing to the top of the block and provided with a 1 central opening of approximately the same diameter as the opening 87. The lower end of stem 88 is secured to a diaphra m 92 centrally thereof, this diaphragm eing disposed in chamber 50 and having its marginal portion glued to shoulder 52 thereof. When the valve is raised the disc 90 closes opening 93 of ring 91 cutting the valve chamber 85 off from the atmosphere and establishing communication between this chamber and diaphragm chamber 50 above the diaphragm 92. Preferably, an annular valve seat of leather or other suitable material, shown at 94, is glued to the upper face of web 86 about the opening 87 thereof to insure a fluid tight closure between the disc 90 and the web for cutting off communication between valve chamber '85 and the upper portion of the diaphragm chamber 50, when the valve is in its lowered position.

Referring to Fig. 8, it will be noted that the closure and supporting strip 60 is of much greater thickness than the block, so as to space the latter a sufficient distance below the cover 13 to permit ready access to the thumb nuts 45 for adjusting the rods 40 to vary the tension of the springs 35. The stri 60 corresponds in width to a strip 95 secured to cover 13, strip 60 seating upon strip 95 and leather packing or gasket 96 being disposed between the two strips to form a fluid tight closure therebetween. The securing screws 15 pass through the two strips 60 and 95 and thread into the cover 13, securing the valve block tightly in position upon the cover. Each of the valve chambers 85 is connected by a short horizontal duct 97 to a vertical duct 98 extending from the under face of strip 60. Duct 98 registers, at its upper end, with the lower end of a duct 99 extending through strip 95, which duct registers in turn, with a duct 100 extending through the cover 13 and opening directly into the bellows 32. The ducts 97, 98, 99 and 100 provide means for admittin atmospheric air to the bellows from valve 0 ambers 85 when the valves caring the discs 90 are in lowered position.

An elbow 101 is secured in the outer end of the supplemental suction channel 62, which extends through the strip 60, this elbow being connected by a short length of rubber tubing 102 to a similar elbow 103 opening into the suction chamber 12. An elbow 104 is secured through the inner end wall of the suction chamber and receives the upper end of conduit 1. An elbow 105 is secured in the outer end wall of suction chamber and is connected to the suction outlet of the channel board by a conduit 106 This connects the suction chamber into the channel board suction system directly in series therewith, which is the referred connection. It will be understoo however, that the suction chamber can be connected into the suction system in any suitable manner to admit air into the same at a proper point to cause corresponding variation in the tension in the channel board for controlling the expression.

The exhauster unit is connected at one end, by a conduit 107 to a governor 108 connected by a conduit 109 to the roll motor 110. A

' tempo valve 111 of suitable type is associated with the governor and is manipulated by a small lever suitably situated on the key bed, for controlling the speed of operation of the roll motor. The other intake of the exhauster unit, at the other end thereof, is connected by a conduit 112 to nipple 113 extending from throat member or box 2. The outer end of throat box 2 is closed by a cover 114 having an air inlet opening 115 closed by a flap valve 116 mounted in a housing 117 secured to the cover. This valve is normally held closed by a wire spring 118 and is opened, when the tension in box 2 reaches a predetermined maximum, by a. finger 119 operated by a bellows 120 secured to the inner wall 121 of the box. This bellows opens directly to atmosphere and is normally held collapsed by a leaf spring 122, the effective strength of which can be adjusted by a screw rod 123. It will be noted that the leaf spring 122 is disposed transversely of the bellows, but in all other respects the construction and operation of the bellows, valve, and associated parts, are the same as the bellows and associated parts for operating the air inlet valves in the device 10. Anipple 124 opens into housing 117 and is connected by conduit 125 to an elbow 126 extending from the inner end of the muffler 11,. The spring 122 is adjusted to permit the valve 116, which is the relief valve previously referred to, to open.

at the desired maximum tension admitting atmospheric air directly into the suction system through the mufiier 11, conduit 125, housing 117 and opening 115.

An intake housing 127 is secured to throat box 2 14). Communication between this housing and the throat box is controlled by a gate valve 127 which is normally open but can be closed by a pneumatic including a diaphragm to which the stem of the valve is secured and a diaphragm chamber to which air is admitted by means of an elbow 128 (Fig. 2). A small tube or conduit 129 (Fig. 1) connects this elbow to the silencervalve (not shown) which is opened to admit air when the roll motor drive is reversed to reroll the music sheet. The gate valve and associated parts are known in this art and need not be further illustrated or described in detail. An elbow 130 (Fig. 1) is secured through the outer side wall of housing 127 and receives the other end of conduit 1 which is connected to the exhaust unit through this housing and the throat box 2. A second elbow 131 (Figs. 1 and 14) extends from the upper end of housing 127 and is connected by a tube 132 to a sustaining device 133 of known type. A nipple 134 extends from the lower end of the housing 127 and is connected by a short tube 135, Y connection 136, and tubes 137 to pneumatics (not shown) for operating the treble and bass rail sections for producing pedalling or loud and soft effects, as is well known. )Vhen rewinding, the gate valve is closed cutting off communication between the suction system of the stack and the exhaust unit, as well as the sustainer and rail operating pneumatics. This effectually prevents any notes being struck while rewinding.

\Vhen the piano is being played the four pneumatics 32 are subject to the suction in the suction chamber 12 due to the creation of a partial vacuum therein. Normally the four primary or pilot control valves are in lowered position due to the suction above and below the diaphragm 72, the diaphragm chambers of these valves being normally all -in communication through the channels 48 and openings 54, as previously described. The uper discs 7 5 are caused by gravity to seat upon the ferrules 57 after which these discs are held seated by atmospheric pressure due to the partial vacuum beneath the discs. In the same manner the discs 90 of valves 89 are normally held in their lowered position due to the communication between the lower portions of the diaphragm chambers 50 and c iaiinels 48 and between the upper portions of these chambers and the suction channels 59 and 62. )Vith all of the valves in lowered position, all of the bellows 32 are in direct communication with the atmosphere. Under such conditions, the bellows having the weakest spring 35 will first respond to the tension in the suction chamber 12 so as to open the corresponding air inlet valve 25. This bellows is the largest one of the series and actuates the flap valve which controls the largest one of the air inlet openings 23. This serves to instantaneously admit a relatively large volume of air into the suction chamber and consequently into the suction system, so as to instantaneously reduce the tension therein very materially to produce the softestor pianissimo playing effect. The proper tension for producing this efi'ect will be maintained in the system so long as none of the tracker bar openings 79, 80, 81 or 82 are uncovered. If it is desired to produce the loudest or fortissimo tone effect the music sheet is provided with one or more perforations disposed to uncover the tracker bar opening 79. This admits atmospheric air beneath the diaphragm of the first or left hand pilot valve as considered in Figure 3, raising this valve and admitting atmosphere beneath the diaphragms of all of the secondary valves and above the diaphragms of the other three primary or pilot valves, by means of the channels and associated openings and ducts. This causes all of the secondary valves to be instantaneously raised cutting off the bellows from the atmosphere and connecting them to the suction chamber 12 by means of the suction channels 59 and 62 in conjunction with the elbows 101 and 103 and the tube 102. The bellows, being subject to the tension in the suction chamber, are held thereby in collapsed or inoperative condition and air cannot be admitted to the suction chamber. Under such conditions, the tension in the system will rise to its maximum value, at which time the relief valve 116 will operate to maintain this value of tension. To obtain the next loudest or forte efiect tracker bar opening is uncovered causin the second primary valve to be raised. This admits atmosphere above the diaphragm of the succeeding primary valves and beneath the diaphragms of the three corresponding secondary valves, which are thus connected to the suction chamber and held inoperative. The lower disc 75 of this valve is held tightly against its seat or ferrule 57 and effectually cuts ofl communication between the diaphragm chamber and passage 53. This prevents the admission of atmospheric air to the first primary valve and, consequently, to the first secondary valve, so that the first or smallest bellows remains open to the amosphere and will expand under the influence of the atmospheric pressure due to the tension in the suction chamber. When this bellows expands the valve finger thereof opens the corresponding flap valve so as to admit a relatively small volume of air into the system producing the proper tension therein to give the forte effect. In the same manner, when tracker bar opening 81 is uncovered to raise the third primary or pilot valve, the smallest and the next to the smallest bellows remain open to the atmosphere, the other two bellows being cut oil from the atmosphere and connected to the suction chamher so as to be held by the tension therein against operation. Of these two bellows remaining open to the atmosphere, the larger one which has the weaker spring will respond first to the tension in the suction chamber, opening the corresponding flap valve and admitting a proper quantity of air into the suction chamber to produce the mezzo-forte effeet. When the last tracker bar opening 82 is uncovered, air is admitted beneath the last or right hand pilot valve diaphragm, raising this valve and admitting air throu h duct 56 beneath the diaphragm of the rig t hand secondary valve. This serves to cut off the first three primary valves and to connect the last or largest bellows 32 to the suction chamher, the other three bellows remaining open to the atmosphere. Of these three bellows the next to the largest, which has the weakest spring of the three, will first respond to the tension in the suction chamber so as to open the corresponding fla valve admitting atmospheric air into t e suction system in proper quantity to produce the piano efiect.

It is to be noted that, in all cases, the valve for producin the desired effect is not opened until the tension in the system has reached the proper degree of value for operating such valve, and air is not admitted to the system continuously at all times but only at such times as it is necessary to produce the desired tone variation. In roducing efiects other than fortissimo and orte the proper bellows, and con is automatlcally selected by the degree of tension in the system itself. This insures instantaneous and accurate operation and gives a very delicate automatic control of the tone variation as well as insuring a clean out lineof distinction or desirable sharpness between the variations in expression. The device as a whole is of extremely simple construction and operation and it is a decided advantage to have all ofthe bellows for operating the flapvalves mounted on the common sup ort of the cover and positioned in a single 0 amber so as to be readily accessible for adjustment or repairs.

What I claim is 1. In an expression control device for player pianos, a suction chamber, means for admitting atmos heric air to the chamber, said means including a pluralit of expansible members .independentl opera le and subject to the tension in the c amber said members being normally all open to the atmosphere and expansion of the members being opposed with difierent degrees of intensity, and means for cutting off communication between one or more of said members selectively and the atmosphere.

2. In an expression control device for player pianos, a suction chamber, a plurality of bellows within the chamber and subject to the air tension therein, means for opening selected ones of the bellows to the atmosphere and for cutting ofi communication between the other bellows and the atmosphere, and means actuated by the bellows open to atmosphere for admitting atmospheric air to the chamber.

3. In an expression control device for pla er pianos, a suction chamber, a lurality of ellows within the chamber an subject to the air tension therein, means opposing expension of the bellows with different degrees of intensity, all of said bellows being normally open to atmosphere, means actuated by ex.- pansion of the bellows for admitting atmospheric air to the chamber, and means for cutting off communication between one or more of said bellows selectively and the atmosphere.

4. In an expression control device for player pianos, a suction chamber, a plurality of bellows within the chamber and subject to the air tension therein, adjustable means opposing ex ansion of the bellows with different degrees 0 intensity, all of said bellows being uently the proper air inlet valvi normally open to atmosphere, means actuated by expansion of the bellows for admitting atmospheric air to the chamber, and means for cutting oii communication between one or more of said bellows selectively and the atmosphere.

5. In an expression control device for player pianos, a suction chamber, a plurality of bellows within the chamber and subject to the air tension therein, means opposing expansion of the bellows with different degrees of intensity, all of said bellows being normally open to atmosphere, means actuated by expansion of the bellows for admitting atmospheric air to the chamber, and means for cutting ofi" communication between one or more of said bellows selectively and the atmosphere and for establishing communication between the suction chamber and the bellows cut oil from atmosphere.

6. In an expression control device for player pianos, a suction chamber having air inlet openings, normally closed valves controlling said openings, a plurality of bellows within the chamber, means actuated by the re spective bellows when expanded for opening the corresponding valves, the valves being opened at different values of tension in said chamber, and means for selectively connecting the bellows to atmosphere or cutting them 0H from atmosphere and connecting them to the suction chamber, optionally.

7 In an expression control device for player pianos, a suction chamber having air inlet openings, valves normally closing said openings, a plurality of bellows within the chamber, means actuated by the respective bellows when expanded for opening the corresponding valves, means opposing expanding of the bellows with dilferent degrees of intensity, and means for selectively connecting the bellows to atmosphere or cutting them 011' from atmosphere, optionally.

8. In an expression control device for player pianos, a suction chamber having air inlet openings, valves normally closing said openings, a plurality of bellows within the chamber, means actuated by the respective bellows when expanded for opening the corresponding valves, said bellows being normally all open to atmosphere, means opposing expanding of the bellows with difierent.

degrees of intensity, and means for selectively cutting the bellows off from atmosphere and connecting them to the suction chamber.

9. In an expression control device for player pianos, a suction chamber having a plurality of air inlet openings, a valve block, valves normally closing said openings, a plurality of bellows disposed within the chamber, means carried by the respective bellows for opening the corresponding valves when said bellows expand, all of the bellows being normally open to the atmosphere, means opposing expanding of the bellows with different degrees of intensity, and means can ricd by the block for selectively cutting the bellows of]? from atmosphere and connecting them to the suction chamber.

10. In an expression control device for player pianos, a suction system including a suction chamber having an air inlet port, a valve controlling said port, yielding means holding the valve closed, a bellows within the chamber and open to the atmosphere, and a valve operating member secured to the expansible member of the bellows for move ment therewith and bearing against the seating face off the valve for opening it in accordance with expansion of said bellows.

11. In an expression control device for player pianos, a suction system including a suction chamber having an air inlet port, a valve controlling said port, yielding means holding the valve closed, a bellows within the chamber and open to the atmosphere, a valve operating member secured to the expansible member of the bellows "for movement therewith and bearing against the seating face of the valve, and adjustable means yieldingly opposing expansion of the bellows.

12. In expression control means for player pianos, a suction system, valves for admitting air into the system in different quantities, pneumatics normally open to the atmosphere and subject to the tension in the system, said pneumatics responding to different values of tension in said system, and means actuated by the pneumatics when expanded for opening the corresponding air valves, said valves being normally closed.

13. In expression control means for player pianos, a suction system, valves for admitting air into the system in difierent quantities, said valves being normally closed, pneumatics normally open to the atmosphere and subject to the tension in the system, said pneumatics responding to difierent values of tension in said system, and means actuated by the pneumatics when expanded for opening the corresponding air valves.

14;. In expression control means for player pianos, a suction system, valves for admitting air into said system, said valves being normally closed, and means controlled by the tension in the system for automatically selecting and opening the air valves in accordance with selected values of tension in the system.

15. An expression control means for player pianos, a suction chamber having air inlet openings, valves normally closing said openings, pneumatics within the chamber and subject to the tension therein, said pneumatics being normally open to the atmosphere and responding to different values of tension in the chamber, and means actuated by the pneumatics when expanded for opening the corresponding valves.

16. In expression control means for player pianos, a suction chamber having air inlet' openings, valves normally closing said openings, a plurality of bellows within the chamber and subject to the tension therein, said bellows being normally open to the atmos phere and responding to different values of tension in the chamber, and means actuated by the movable leaves of the bellows for open ing the corresponding valves upon extension of the bellows.

17 In expression control means for player pianos, suction producing means, a suction chamber having air inlet openings and in communication with the suction producing means, valves normally closing said openings, pneumatics within the suction chamber and subject to the tension therein, said pneumatics being normally open to the atmosphere and responding to different values of tension in the chamber, means actuated by the pneumatics when expanded for opening the corresponding valves, and means for selectively connecting the pneumatics to said suction producing means and preventing expanding of the pneumatics.

18. In expression control means for player pianos, suction producing means, a suction chamber having air inlet openings and in communication with the suction producing means, val'ves normally closing said openings, pneumatics within the suction chamber and sub'ect to the tension therein, said pneumatics eing normally open to the atmosphere and responding to different values of tension in the chamber, means actuated by the pneumatics when expanded for opening the corresponding valves, means for connecting any selected one or all of the pneumatics to the suction producing means, and a relief valve adjusted to admit air to said suction producing means when the tension created thereby reaches a predetermined value.

In witness whereof, I hereunto subscribe my name this 29th day of March, 1927.

GUSTAV A. FORSBERG. 

